The invention relates generally to operating methods and apparatus relating to automated mechanical transmissions (AMT's) and more particularly to a method and apparatus for selecting one of a plurality of automated mechanical transmission shift scheduling modes and associated software.
Automated mechanical transmissions may be accurately characterized as comprising two components: a multiple speed gear change transmission having pneumatic, electric or hydraulic actuators which control translation of transmission shift rails and a microprocessor based electronic control unit which receives data from multiple sensors which sense, for example, shaft speeds, engine operation and operator commands and provides transmission and clutch actuators with control signals based upon stored software embodying specific shift scheduling modes.
While the transmission and actuators are fairly characterized as sophisticated, it is the operating algorithms and related memory and control systems of the electronic control unit which controls overall operation of the transmission and its actuators to which the designation sophisticated is most aptly applied. The engineering and program or software choices embodied in the controller and algorithms are primarily responsible for satisfying the vehicle operator, achieving smooth, predictable and safe vehicle operation, providing improved fuel efficiency and extending the service life of components such as the master friction clutch.
One of the benefits of automated mechanical transmissions and particularly the algorithms and data systems of the associated electronic control units is the ability to provide a transmission shift scheduling mode optimized for a particular operating condition or set of conditions such as performance, fuel economy, a routinely encountered operating condition such as urban congestion or steep grade associated with mountain operation, a particular tractor manufacturer's operating preferences, even a particular vehicle operator's preferences or any other specific or unique operating parameters.
Generally speaking, to change from one shift scheduling mode to another, that is, to change from one set of operating algorithms to another, requires removal or deletion of the undesired software and downloading of the new software. This activity is preferably undertaken only by a tractor dealership or authorized service organization and typically requires expensive service tools and highly skilled technicians.
The present invention presents a method and apparatus for addressing these difficulties of the prior art and providing improved automated mechanical transmission performance.